Transit seat with contoured plastic shell

ABSTRACT

A passenger seat for public transportation vehicles includes a frame with a recessed seat area for receiving a one-piece molded plastic shell which is provided with a contoured seat and back area for a single passenger or each of two or more side-by-side passengers. Separate replaceable seat and back insert panels are received in the seat and back contoured portions which act to retain passengers in place during turns while providing versatility and modification possibilities in seat and back aesthetics. Means are provided for adjusting the positions of the insert panels during attachment to match their configurations to the contoured portions of the shell.

U116 \li Barecki States Patent 1 Mar. 25, 1975 1 1 TRANSIT SEAT WITH CONTOURED PLASTIC SHELL [75] Inventor: Chester J. Barecki, Grand Rapids,

Mich.

[73] Assignee: American Seating Company, Grand Rapids, Mich.

221 Filed: May 24,1973

211 Appl. No.: 363,716

Related US. Application Data [63] Continuation-impart of Ser. No. 232,430, March 7,

1972, Pat. No. 3,747,978.

[52] 11.8. C1 297/445, 297/455, 297/458 [51] Int. Cl. A47c 7/02 [58] Field of Search 297/445, 232, 257, 258,

297/259, 260, DIG. 2; 312/296, 257 A; 5/3532; 108/158, 159

[56] References Cited UNITED STATES PATENTS 667,591 2/1901 Smith 297/458 1,188,453 6/1916 Johnson.... 297/459 1,581,257 4/1926 Wedge 108/158 2,153,596 4/1939 Schermerhorn 297/458 3,025,105 3/1926 Nash 297/D1G. 2

3,189,379 6/1965 Potter 108/159 X 3,309,051 3/1967 Pina 108/158 3,556,592 1/1971 Antoine 297/460 3,669,499 6/1972 Semplonius 297/460 3,734,561 5/1973 Barecki et al 297/D1G. 2 3,749,442 7/1973 Berg et a1. 297/458 FOREIGN PATENTS OR APPLICATIONS 614,666 1/1958 Italy 297/D1G. 2

Primary Examiner-Pau1 R. Gilliam Assistant Examiner-Carl F. Pietruszka Attorney, Agent, or FirmPrice, Heneveld, Huizenga & Cooper [57] ABSTRACT A passenger seat for public transportation vehicles includes a frame with a recessed seat area for receiving a onepiece molded plastic shell which is provided with a contoured seat and back area for a single passenger or each of two or more side-by-side passengers. Separate replaceable seat and back insert panels are received in the seat and back contoured portions which act to retain passengers in place during turns while providing versatility and modification possibilities in seat and back aesthetics.

8 Claims, 18 Drawing Figures PATENIED MAR 2 5 I975 sumun g PMENTEDMAR251975 7 sum a m g g TRANSIT SEAT WITH CONTOURED PLASTIC SHELL CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part application of copending, coassigned application Ser. No. 232,430, filed Mar. 7, 1972, and entitled TRANSIT SEAT WITH CONTOURED PLASTIC SHELL, now US. Pat. No. 3,474,978 issued July 24, 1973.

BACKGROUND OF THE INVENTION The present invention relates to passenger seats; and more particularly, it relates to a passenger seat designed for use in public transportation vehicles, such as buses, rapid transit trains, etc.

It is desirable to provide such a seat that is not only economical to manufacture, rugged and durable in use, safe in the event of a crash, and easy to maintain but it is also important to provide versatility in the seating and to have a pleasant aesthetic appearance.

In connection with safety, the primary objective to prevent injury is to retain the occupant in his seat under conditions where the vehicle generates forces due to deceleration or component lateral forces due to a change of direction, as in sharp turns.

A properly designed seat contour, with sufficient inclined area will retain the occupant up to one acceleration of gravity, 1 g, whereas a poorly developed contour will not prevent the occupant from sliding off the Seat at forces below one-half g.

The seat must also absorb energy and moderate the magnitude of energy transmitted to an occupant. The

seat must act as a compartment to restrain the occupant and prevent his becoming a projectile in the event of a crash. The seat must serve as a protective shield to ward off blows from projections of collapsing structures. Above all, the seat must be structurally crashworthy to provide desirable deformation characteristics and still sufficiently strong to prevent disintegration.

The rear surface of seat should not only be aesthetically pleasing, but it should be devoid of hazardous members that could become lethal objects in the event of crash.

Finally, it is desirable that the seat be as free as possible from dirt-collecting and clothing-snagging crevices.

SUMMARY OF THE INVENTION The transit seat of the present invention provides a frame having a recessed seat area for receiving a onepiece molded plastic shell which is provided with contoured seat and back areas for each passenger held by the seat. A single pedestal having a rectangular cross section elongated in the fore-and-aft direction is lo cated beneath the seat spaced inwardly of the aisle end of the seat for supporting it. The other end of the seat is preferably connected to a wall of the vehicle.

Separate replaceable seat and back insert panels are received in the contoured positions of the seat and back; and the contours are such that even though seat and back insert panels are attached to the seat and back, there is still sufficient contour to retain passengers in place during turns of the vehicle. This has been found to be of significant advantage, particularly in buses and other public transportation vehicles wherein the seats are located relatively closely behind a forward seat. In other words, an aisle rail need not be provided with each seat, and this facilitates ingress and egress, while at the same time, a passenger has a feeling of stability during the various conditions of riding.

Any number of different types of seat and back insert panels may be secured to the plastic shell, and this adds versatility in the use of the basic seat. For example, in areas where vandalism to public vehicles may be high, plastic insert panels may be used. On the other hand, where wear is of primary concern, vinyl-clad steel insert panels may be preferred. A note of luxury may be added by padding the insert panels. This feature further adds to the versatility in the aesthetic appearance of the seat without significantly adding to cost and still permits the proper contour for all inserts for lateral retention of occupants. The color scheme can be varied from vehicle to vehicle or within a given vehicle, and the entire color scheme of the seating may be changed with minimal cost. Further, the invention provides a novel design for the seat and back insert panels which ensures a tight, uniform fit in the shell recesses which virtually eliminates dirt-collecting and clothingsnagging crevices and which makes prying the insert panels out by vandals nearly impossible.

A grab rail of round tubular steel grabs is inserted into open ends of square side frame tubes beneath a top flange in the shell, and this softens the lines of the seat and enhances its appearance by hiding from view this connection. Thus, square or rectangular tubing may be used for the frame with its greater strength per unit across sectional area, and round tubing may be used for the grab rail since it is more comfortable.

Another feature of the invention is that it permits the construction of a seat employing a plastic shell which is securely supported by its frame, so that the seat will not disintegrate in the event of a crash. To this end, the shell is secured at the top of the back and along the leg support bar.

The pedestal is secured to a transverse frame member spaced inwardly from the aisle, as mentioned, and this eliminates under-seat obstructions to persons moving up and down the aisle, which has been a disadvantage in certain prior seats. Further, the pedestal is pro vided with a smoothly curved foot pad to facilitate cleaning around the aisle, and to eliminate any dirtcatching projections or recesses. To further facilitate cleaning, the one-piece plastic shell when fitted with properly contoured insert panels also does not have any dirt-catching pockets as explained above.

Certain aspects of the present invention are disclosed in but not claimed in copending, coassigned applications in which I am co-inventor, namely, the applications of Barecki and Karrip for RAPID TRANSIT SEATING, Ser. No. 157,345, filed June 28, l97l,and for SEAT FOR URBAN MASS TRANSIT VEHI- CLES, Ser. No. 280,793, filed Aug. 15, 1972, which are directed to a cantilever transit seat.

Other features and advantages of the present invention will be apparent to persons skilled in the art from the following detailed description of the preferred embodiments accompanied by the attached drawings wherein identical reference numerals will refer to like parts in the various figures.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front perspective view of a transit seat, taken from the aisle, constructed according to the present invention;

FIG. 2 is a rear perspective view of the transit seat of FIG. 1, also taken from the aisle;

FIG. 3 is a view similar to that of FIG. 2 of a modification of the seat, excluding a rear cover panel;

FIGS. 4, 5, and 6 are, respectively, plan, front, and aisle side views of the seat of FIG. 1;

FIG. 7 is an exploded perspective view of an entire seat constructed according to the present invention;

FIG. 8 is a side cross-sectional view taken along the plane VIII-VIII of FIG.

FIG. 9 is a front cross-sectional view taken along the plane IX-IX of FIG. 4;

FIG. 10 is a bottom cross-sectional view taken along the plane X-X of FIG. 5;

FIG. 11 is a bottom view of one seat insert panel; FIGS. 12-17 are similar cross-sectional views taken through the plane XII-XII of FIG. 4 to show different insert panels and methods of attaching the insert panels, depending upon the construction of the panel; and

FIG. 18 is a schematic sectional view similar to FIG. 11 showing a preferred insert panel.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIGS. l7, a transit seat generally designated 20 includes a square tubular frame 21 supported by a column or pedestal 22 atop an oval flared foot 23 preferably having two mounting holes 24 and 25. The column has a rectangular cross section which is elongated in the fore-and-aft direction of the seat. The frame 21 is attached to the wall of the vehicle by two L-shaped wall mounting brackets 26 and 27; and the seat of this embodiment is provided with a round tubular grab rail 28 inserted into open upper ends 29 and 30 of a pair of side L-shaped square tubes 31, 32 as best seen in FIG. 7. The frame 21 supports a singlepiece, plastic (preferably fiberglass) shell 33 is preferably decoratively covered by seat insert panels 34, 35 as well as back insert panels 36, 37 for side-by-side passenger accommodation. The insert panels are received in appropriately provided recesses 38, 39, 40, and 41. A suitably shaped back cover panel 42 is also provided, but may be eliminated as in the embodiment of FIG. 3, which is otherwise similar. v

The contouring of the recesses 38-41, even when the associated insert panels 34-37 have been secured to the shell, is maintained and is smoothly blended into the periphery of shell 33 by providing raised portions 33a around the side periphery of the recesses. This is considered an important feature of the present invention in that it provides for retention of the seated passengers even during sharp turns. The raised portions 33a enhance the passenger retention since they create, in effect, a deeper contour at both sides of the base of the seats at at both sides of the back and shoulder areas where most needed. Consequently, the passenger has a sense of stability in riding, so much so that the need for a side arm rail is obviated. This is important in the case of transit seating because of the close spacing between one seat and the seat in front of it. If a side rail were in- I cluded, ingress and egress to the seat would be partially obstructed. Thus, the insert panels 34-37 are characterized in'that they conform to the contour of their associated recesses; and, secondly, they are relatively thin and of substantially uniform thickness so as to maintain their respective contours and retain the body of a seated passenger.

The plastic shell 33 rests on a raised transverse front rail 43 of square tubing and a similar upper rear rail 44 and is attached to the square tubular frame by means of several tubular rivets 45 inserted through the side flanges 46 of the shell and the L-shaped end tubes 31 and 32. The holes 47 for the tubular rivets are drilled at the time of assembly so that there does not have to be any matching of holes in the two joining pieces. Tubular rivets are purposely omitted from the front edge flange 48 to avoid any snagging of clothing.

A lower rear cross tube 50 is purposely depressed in its center portion in order to provide clearance for the bucket-type recesses 38 and 39 of the shell. This can be seen best in FIG. 3. This cross tube 50 is connected to the front cross tube 43 by a forwardly extending tube 51. The tube 51 adds rigidity to the frame structure and also serves to strengthen the location at which the supporting column 22 is secured to the frame-The back cover panel 42 is attached to the frame 21 with threadcutting screws 52; and it is also preferably molded from a single sheet of plastic, such as fiberglass.

Turning more specifically to the design of insert panels 3437, it is more important that the insert panels have a very tight and uniform fit within the respective recesses 38-41 to eliminate undesirable gaps or crevices between the peripheries of the insert panels and the peripheries of the recesses. Such gaps or crevices not only provide dirt-collecting pockets and clothessnagging hazards, they also make it more easy for the inserts to be pryed free from the recesses by vandals. Further, an improper fit of the insert panels in the recesses also results in a certain amount of discomfort to the passenger. The insert panel design of the present invention eliminates these problems by providing a tight, uniform fit of the insert panels in their respective recesses.

It has been found that no matter what material the insert panels are made of, e.g., plastic such as fiberglass or vinyl-clad steel, it is difficult with current commercial production methods to mass produce the seat shells and insert panels with the degree of dimensional accuracy to ensure a tight and uniform fit of the insert panels in the recesses in every assembled seat. Even the most minor undulations or deviations in the insert panels or seating shell recesses are accentuated because of the complex contour of the panels and recesses for maximum seating comfort and safety. Thus, to overcome the effect of these minor manufacturing deviations of the fit of the inserts in the recesses, the insert panels of the present invention are designed so that when the panels are assembled in the recesses, there is an air gap between the underside of the panels and the top surface of the recesses. This air gap permits enough selective adjustment latitude in securing the insert panels to the recesses to overcome any deviations or undulations in the insert panels or seat shell recesses.

The insert panels of the present invention may be of several different designs. The preferred insert panel design is shown in FIGS. 8-12 and 18. As best seen in FIGS. 11 and 12, the insert panel 34, which is preferably made of fiberglass, is provided with a peripheral integral depending bead 53 of a sufficient height so that when the insert panel is secured in said recess, the top peripheries of insert panel 34 and recess 38 will be substantially flush. A plurality of anchoring bosses 58, preferably four, are provided inwardly of bead 53 on the underside of the insert panel which have a crosssectional height less than the cross-sectional height of bead 53 and in which are embedded or otherwise affixed anchoring means such as nut members 59.

Further, it is preferred that depending bead 53 be angled downwardly inwardly from the peripheral edge of the insert panel and that the side wall 38a of recess 38 have a corresponding downward, inward angle for ensuring a minimum gap between the periphery of the insert panel and the periphery of the recess. The cooperation and function of the bead 53 and recess wall 38a angles are best shown in schematic FIG. 18. As shown, when insert panel 34 is placed in recess 38, there is an initial gap Y between the peripheries of the insert panel and the recess. However, when insert panel 34 is drawn toward recess 38 by screw means 60 to the position shown in phantom, the gap Y is decreased to Z because of the angles of bead 53 and wall 38a. Thus, as the plurality of screws 60 are selectively adjusted, the gap between the peripheries of wall 38a and panel 34 can be virtually eliminated. Further, the insert and recess can be designed to achieve any predetermined final gap Z by specifying the angle X of bead 53 and wall 38a, and the initial clearance C between the bottom of bead 53 and recess 38 since:

For example, with an initial gap Y of 0.040 inch, if angle X is 35 and clearance C is 0.030 inch, the final gap Z will be equal to 0.040 0.030(0.7002) or 0.019 inch, less than half of the initial gap.

Thus, during assembly, the insert panel is placed in the recess and appropriate attachment means such as screws 60 are engaged with nut means 59 through apertures in the recesses in shell 53. Because of air gap 57 between the insert panel and the surface of the recess, screws 60 can be selectively tightened drawing the respective portions of the insert panel toward the recess until a uniform fit of the insert panel in the recess is achieved, while minimizing gap Z. Thus, the selective adjustment permitted by air gap 57 and the plurality of attachment means 59 and 60 permits compensation to be made for any minor deviations or undulations in the insert panels or in the recesses of the seat shell. Further, depending peripheral bead 53 and angled wall 38a not only ensures a minimum gap between the panel and recess peripheries, it also provides peripheral support for the panel to eliminate depression of the insert panel below the top periphery of the recesses. Also the bead 57 produces a tension on the attachment screws which results in a locking action.

A second typeof insert panel is shown in FIGS. 13 and 14. As seen therein, a vinyl-clad steel panel 61 has a backing strip of rubber 62 to raise the panel to the level of the shell 33 while acting as a shock-absorbing cushion. It is attached to the shell by the use of tee nuts 63 and washers 64 used as spacers. As with the preferred insert panel discussed above, the air gap 57 between the insert panel and the recess surface permits the selective tightening of the tee nuts to achieve a uniform tight fit of the panel in the recess.

once again, the air gap 57 is provided for the selective compensating adjustments.

FIG. 17 shows the use of studs 68 and acorn nuts 69 in place of tee nuts and screws. Thus substitution may be used on any of the disclosed variations:

As will be obvious to those skilled in the art, a number of variations can be made in the transit seat of the present invention without departing from the spirit thereof. For example, while three different novel insert panels have been described and illustrated, various means of attachment may be employed as well as various means for achieving the air gap between the insert panels and the seat shell to permit the selective compensating adjustment during the attachment of the insert panel to the seat recess. Therefore, the scope of the present invention is deemed to be limited only by the following appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a transit seat comprising a plastic shell having at least one contoured seat recess for receipt of a seat insert panel, said recess having a peripheral wall of a predetermined height and a bottom portion adjoining and adjacent at least said peripheral wall, the improvement comprising: a seat insert panel having a peripheral side wall defining a peripheral outline substantially corresponding to the peripheral outline of said seat recess; spacing means having a predetermined height and extending below the bottom of said insert panel, adjacent said peripheral side wall, and between said panel bottom and recess bottom portion for positioning portions of said insert panel in spaced relationship to said seat recess; said spacing means providing an air gap between the bottom of said insert panel and said seat recess; at least one of said peripheral recess wall and panel peripheral side wall being tapered downwardly and inwardly toward the center of said recess at a predetermined angle; attachment means for securing said insert panel in said recess including-a plurality of fasteners spaced inwardly of said peripheral spacing means and extending between said insert panel and recess bottom portion; said attachment means providing an attachment of said insert panel to said shell within said recess by drawing said panel into said recess such that as said spacing means contacts said recess bottom portion said air gap, provided by said spacing means, and the said predetermined angle of said one tapered wall cooperate to accommodate any deviations or undulations in the insert panel or seat shell recess and yield a tight uniform fit of the periphery of said insert panel with the periphery of said recess and space the top of said insert panel above said bottom portion of said recess such that said panel top is substantially flush with the top edge of said recess peripheral wall.

2. The transit seat according to claim 1 wherein said spacing means comprises a peripheral, depending bead formed on the underside of said insert panel from the same material as said insert panel.

3. A transit seat according to claim 2 including a plurality of nuts for cooperating with said threaded fasteners, one of each of said cooperating nuts and threaded fasteners being embedded in depending bosses on the underside of said insert panel inwardly of said bead, the height of said depending bosses being less than the height of said bead, and the other of each of said coop erating nuts and threaded fasteners engaging said one of each of said nut and threaded fasteners through apertures in the contoured seat recess portion of said transist seat so that the cooperating nuts and threaded fasteners can be selectively adjusted.

4. A transit seat according to claim 3 wherein said plastic shell has raised portions at least adjacent the rear sides of said seat recess which blend with and continue the contour of said recess above the top periphery of said recess.

5. A transit seat according to claim 1 wherein said peripheral spacing means comprises a strip of resilient material separate from said insert panel and recess be tween the underside of the periphery of said insert panel and the periphery of said recess.

6. In a transit seat comprising a plastic shell having at least one contoured seat recess for receipt of a seat insert panel, said recess having a peripheral wall of a predetermined height and a bottom portion adjoining and adjacent at least said peripheral wall, the improvement comprising:

a seat insert panel having a peripheral side wall, a contour substantially corresponding to the contour of said seat recess, and a peripheral, integral, depending bead formed from the same material as said seat insert panel and extending below the bottom of said seat insert panel a predetermined distance, said depending bead being adjacent said seat insert panel peripheral wall and between said panel bottom and recess bottom portion for positioning portions of said seat insert panel in spaced relationship to said seat recess providing an air gap between the bottom of said insert panel and said seat recess; said peripheral side wall of said insert panel extending along the edges of both said panel and said depending bead and being tapered downwardly and inwardly toward the center of said recess at a predetermined angle; said peripheral wall of said recess also being tapered downwardly and inwardly toward the center of said recess at a predetermined angle; and attachment means for securing said insert panel in said recess including a plurality of threaded fasteners spaced inwardly of said depending bead and extending between the bottom of said insert panel and said recess bottom portion whereby when said insert panel is attached to said shell within said recess by drawing said panel into said recess with said threaded fasteners such that depending bead contacts said recess bottom portion, said air gap is reduced, and said extending distance of said depending bead and said predetermined angles of said tapered insert side wall and said tapered, recess peripheral wall cooperate to both yield a tight uniform fit of the periphery of said insert panel with the periphery of said recess to substantially eliminate spaces therebetween and to space the top of said insert panel above said bottom portion of said recess such that said panel top is substantially flush with the top of said recess peripheral wall.

7. In a transit seat comprising a plastic shell having at least one contoured seat recess for receipt of a seat insert panel, said recess having a peripheral wall of a predetermined height and a bottom portion adjoining and adjacent at least said peripheral wall, said recess peripheral wall tapering inwardly and downwardly toward the center of said recess, the improvement comprising:

a seat insert panel having a peripheral side wall and a contour substantially corresponding to the contour of said seat recess;

a separate strip of resilient material having a predetermined thickness and positioned adjacent said insert panel side wall below the bottom of said insert panel and between the bottom of said panel and said recess bottom portion for positioning portions of said insert panel in spaced relationship to said seat recess providing an air gap between the bottom of said insert panel and said seat recess inwardly of said separate strip; and

attachment means for securing said insert panel in said recess including a plurality of threaded fasteners spaced inwardly of said panel side wall and separate strip toward the center of said panel and extending between said insert panel and recessed bottom portion whereby when said insert panel is attached to said shell within said recess by drawing said panel into said recess with said threaded fasteners such that said seperate strip contacts said recessed bottom portion, said air gap is reduced and said predetermined thickness of said separate strip and said predetermined angle of said tapered recessed peripheral wall cooperate to both yield a tight uniform fit of the periphery of said insert panel with the periphery of said recess to substantially eliminate spaces therebetween and to space the top of said insert panel above said bottom portion of said recess such that said panel top is substantially flush with the top of said recess peripheral wall.

8. In a transit seat comprising a rigid plastic shell having at least one contoured seat surface with a recess provided for receipt of a seat insert panel having a contoured seat surface merging with said contoured seat surface of said shell, said recess having a peripheral wall of a predetermined height and a contoured bottom portion adjoining and adjacent at least said peripheral wall, the improvement comprising: a seat insert panel having a peripheral side wall defining a peripheral outline substantially corresponding to the peripheral outline of said seat recess; peripheral spacing means having a predetermined height and extending below the bottom of said insert panel, adjacent said peripheral side wall, and between said panel bottom and recess bottom portion for positioning the remaining inwardly located major portions of the bottom of said insert panel in spaced relationship to said seat recess; said spacing means providing an air gap between the said major portions of the bottom of said insert panel and said seat recess; attachment means for securing said insert panel in said recess including a plurality of fasteners spaced inwardly of said peripheral spacing means and extending between said major portions of said insert panel and said recess bottom portion, said attachment means providing an attachment of said insert panel to said shell within said recess by drawing said panel into said recess such that as said spacing means contacts said recess bottom portion, the air gap provided by said spacing means functions to accommodate any deviations or undulations in the said major portions of the bottom of such insert panel or in the contoured bottom portion of said seat shell recess and to space the contoured seat surfaceof said insert panel above said bottom portion of said recess such that said panel seat surface is substantially flush in the area where it merges with the contoured seat surface of said shell.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,873,155

DATED March 25 1975 v r0 5 Chester J. Barecki It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Abstract, after the last sentence;

Please add "Means are provided for adjusting the positions of the insert panels during attachment to match their configurations to the contoured portions of the shell.--

Column 1, line 9;

"3 ,474 ,978" should be -3,747 ,978-

Signed and Scaled this twenty-second Day Of July 1975 [SEAL] Attest.

RUTH cfMAsoN Alresrr'ng Officer C. MARSHALL DANN Commissioner of Paronrs and Trademarks 

1. In a transit seat comprising a plastic shell having at least one contoured seat recess for receipt of a seat insert panel, saiD recess having a peripheral wall of a predetermined height and a bottom portion adjoining and adjacent at least said peripheral wall, the improvement comprising: a seat insert panel having a peripheral side wall defining a peripheral outline substantially corresponding to the peripheral outline of said seat recess; spacing means having a predetermined height and extending below the bottom of said insert panel, adjacent said peripheral side wall, and between said panel bottom and recess bottom portion for positioning portions of said insert panel in spaced relationship to said seat recess; said spacing means providing an air gap between the bottom of said insert panel and said seat recess; at least one of said peripheral recess wall and panel peripheral side wall being tapered downwardly and inwardly toward the center of said recess at a predetermined angle; attachment means for securing said insert panel in said recess including a plurality of fasteners spaced inwardly of said peripheral spacing means and extending between said insert panel and recess bottom portion; said attachment means providing an attachment of said insert panel to said shell within said recess by drawing said panel into said recess such that as said spacing means contacts said recess bottom portion said air gap, provided by said spacing means, and the said predetermined angle of said one tapered wall cooperate to accommodate any deviations or undulations in the insert panel or seat shell recess and yield a tight uniform fit of the periphery of said insert panel with the periphery of said recess and space the top of said insert panel above said bottom portion of said recess such that said panel top is substantially flush with the top edge of said recess peripheral wall.
 2. The transit seat according to claim 1 wherein said spacing means comprises a peripheral, depending bead formed on the underside of said insert panel from the same material as said insert panel.
 3. A transit seat according to claim 2 including a plurality of nuts for cooperating with said threaded fasteners, one of each of said cooperating nuts and threaded fasteners being embedded in depending bosses on the underside of said insert panel inwardly of said bead, the height of said depending bosses being less than the height of said bead, and the other of each of said cooperating nuts and threaded fasteners engaging said one of each of said nut and threaded fasteners through apertures in the contoured seat recess portion of said transist seat so that the cooperating nuts and threaded fasteners can be selectively adjusted.
 4. A transit seat according to claim 3 wherein said plastic shell has raised portions at least adjacent the rear sides of said seat recess which blend with and continue the contour of said recess above the top periphery of said recess.
 5. A transit seat according to claim 1 wherein said peripheral spacing means comprises a strip of resilient material separate from said insert panel and recess between the underside of the periphery of said insert panel and the periphery of said recess.
 6. In a transit seat comprising a plastic shell having at least one contoured seat recess for receipt of a seat insert panel, said recess having a peripheral wall of a predetermined height and a bottom portion adjoining and adjacent at least said peripheral wall, the improvement comprising: a seat insert panel having a peripheral side wall, a contour substantially corresponding to the contour of said seat recess, and a peripheral, integral, depending bead formed from the same material as said seat insert panel and extending below the bottom of said seat insert panel a predetermined distance, said depending bead being adjacent said seat insert panel peripheral wall and between said panel bottom and recess bottom portion for positioning portions of said seat insert panel in spaced relationship to said seat recess providing an air gap between the bottom of said insert panel and said seat recess; said peripheral side wall oF said insert panel extending along the edges of both said panel and said depending bead and being tapered downwardly and inwardly toward the center of said recess at a predetermined angle; said peripheral wall of said recess also being tapered downwardly and inwardly toward the center of said recess at a predetermined angle; and attachment means for securing said insert panel in said recess including a plurality of threaded fasteners spaced inwardly of said depending bead and extending between the bottom of said insert panel and said recess bottom portion whereby when said insert panel is attached to said shell within said recess by drawing said panel into said recess with said threaded fasteners such that depending bead contacts said recess bottom portion, said air gap is reduced, and said extending distance of said depending bead and said predetermined angles of said tapered insert side wall and said tapered, recess peripheral wall cooperate to both yield a tight uniform fit of the periphery of said insert panel with the periphery of said recess to substantially eliminate spaces therebetween and to space the top of said insert panel above said bottom portion of said recess such that said panel top is substantially flush with the top of said recess peripheral wall.
 7. In a transit seat comprising a plastic shell having at least one contoured seat recess for receipt of a seat insert panel, said recess having a peripheral wall of a predetermined height and a bottom portion adjoining and adjacent at least said peripheral wall, said recess peripheral wall tapering inwardly and downwardly toward the center of said recess, the improvement comprising: a seat insert panel having a peripheral side wall and a contour substantially corresponding to the contour of said seat recess; a separate strip of resilient material having a predetermined thickness and positioned adjacent said insert panel side wall below the bottom of said insert panel and between the bottom of said panel and said recess bottom portion for positioning portions of said insert panel in spaced relationship to said seat recess providing an air gap between the bottom of said insert panel and said seat recess inwardly of said separate strip; and attachment means for securing said insert panel in said recess including a plurality of threaded fasteners spaced inwardly of said panel side wall and separate strip toward the center of said panel and extending between said insert panel and recessed bottom portion whereby when said insert panel is attached to said shell within said recess by drawing said panel into said recess with said threaded fasteners such that said seperate strip contacts said recessed bottom portion, said air gap is reduced and said predetermined thickness of said separate strip and said predetermined angle of said tapered recessed peripheral wall cooperate to both yield a tight uniform fit of the periphery of said insert panel with the periphery of said recess to substantially eliminate spaces therebetween and to space the top of said insert panel above said bottom portion of said recess such that said panel top is substantially flush with the top of said recess peripheral wall.
 8. In a transit seat comprising a rigid plastic shell having at least one contoured seat surface with a recess provided for receipt of a seat insert panel having a contoured seat surface merging with said contoured seat surface of said shell, said recess having a peripheral wall of a predetermined height and a contoured bottom portion adjoining and adjacent at least said peripheral wall, the improvement comprising: a seat insert panel having a peripheral side wall defining a peripheral outline substantially corresponding to the peripheral outline of said seat recess; peripheral spacing means having a predetermined height and extending below the bottom of said insert panel, adjacent said peripheral side wall, and between said panel bottom and recess bottom portion for positioning the remaining inwardly located major portions of the bottom of said insert panel in spaced relationship to said seat recess; said spacing means providing an air gap between the said major portions of the bottom of said insert panel and said seat recess; attachment means for securing said insert panel in said recess including a plurality of fasteners spaced inwardly of said peripheral spacing means and extending between said major portions of said insert panel and said recess bottom portion, said attachment means providing an attachment of said insert panel to said shell within said recess by drawing said panel into said recess such that as said spacing means contacts said recess bottom portion, the air gap provided by said spacing means functions to accommodate any deviations or undulations in the said major portions of the bottom of such insert panel or in the contoured bottom portion of said seat shell recess and to space the contoured seat surface of said insert panel above said bottom portion of said recess such that said panel seat surface is substantially flush in the area where it merges with the contoured seat surface of said shell. 